The present invention refers to a variable capacitor, in particular a vacuum capacitor, in which stationary capacitor disks and capacitor disks which are linearly displaceable with respect to the former ones and disposed on a motor-driven screw are accommodated in a housing, and safety end switches and a position indicator device are associated to the displaceable capacitor disks.
Prior embodiments of variable capacitors of this type, which are generally used in HF technique, medical technique, and the like, have already been provided with safety end switches which are coupled to the movement of the displaceable capacitor disks in one way or another. The purpose of such end switches is to limit the movement of the displaceable portion of the capacitor on both sides. It is also known to provide such capacitors with position indicators which are disposed in parallel to the proper capacitors. Like the adjusting screw itself, they are driven by a gearwheel or a belt drive acting on an adjusting screw.
However, such capacitors having a drive, a position indicator, and end switches are not only unhandy and bulky, but also relatively unprecise because of the unavoidable play of the drive, which is why they cannot provide the reproducibility which may be desired in certain cases.